The government spent nearly £200,000 putting out cones to turn the M20 into a lorry park in preparation for a no-deal Brexit - then took them away again a day later.
A Freedom of Information (FOI) request revealed the cost of activating Operation Brock on 28 October - three days before the UK was due to leave the EU - was £107,000.
But a further £88,000 was spent deactivating it on 29 October.
Highways England, a company owned by the Department for Transport, planned to put a contraflow system in place on the motorway leading down to the Kent coast so that one side of the M20 was only used by heavy goods vehicles.
This was due to fears there would be delays with customs checks at cross-Channel ports if the UK left the EU without a deal, creating a back-log of vehicles leading from Dover.
The plan swung into action despite the fact that MPs had passed the Benn Act delaying a no-deal Brexit.
Just hours after highways officials began the process of putting out the 7,500 cones, Boris Johnson sent a letter to Brussels requesting the Article 50 deadline be extended to 31 January.
After it was accepted by the European Council, Highways England confirmed Operation Brock was being stood down.
In response to the FOI asking how much this cost they told Civil Service World’s sister title PoliticsHome: “The costs associated with the activation of the contraflow was £107,847.22.
“Installing and removing traffic management is a significant operation and is a main consideration in any road scheme.
“In the case of Operation Brock it involved installing crossover points in the central reservation, altering the road layout and putting out 7,500 traffic cones and 350 signs.”
The further costs “associated with the deactivation of the contraflow were £88,547.12," it confirmed.
In total Highways England has been allocated £35m for the operation, £30m for the M20, and £5m assigned to adapting the nearby M26 “as an additional contingency measure”.
It was also put in place back in March ahead of the first Article 50 deadline but was deactivated three weeks later once the extension to October 31 was agreed.